aboutsummaryrefslogtreecommitdiff
path: root/openssl/ssl/d1_pkt.c
diff options
context:
space:
mode:
authormarha <marha@users.sourceforge.net>2013-02-13 09:48:21 +0100
committermarha <marha@users.sourceforge.net>2013-02-13 09:51:39 +0100
commitaaf21968deb85b635cb6aa6544df233ea5981346 (patch)
tree450a73e83a174325e6a69ad69eb4011c2eb7df8c /openssl/ssl/d1_pkt.c
parent8add148a4cf71b8bdab05a6b7e14824b5062da5e (diff)
downloadvcxsrv-aaf21968deb85b635cb6aa6544df233ea5981346.tar.gz
vcxsrv-aaf21968deb85b635cb6aa6544df233ea5981346.tar.bz2
vcxsrv-aaf21968deb85b635cb6aa6544df233ea5981346.zip
Update to following packages:
openssl-1.0.1e freetype-2.4.11
Diffstat (limited to 'openssl/ssl/d1_pkt.c')
-rw-r--r--openssl/ssl/d1_pkt.c91
1 files changed, 54 insertions, 37 deletions
diff --git a/openssl/ssl/d1_pkt.c b/openssl/ssl/d1_pkt.c
index 987af6083..0bf87be6d 100644
--- a/openssl/ssl/d1_pkt.c
+++ b/openssl/ssl/d1_pkt.c
@@ -376,15 +376,11 @@ static int
dtls1_process_record(SSL *s)
{
int i,al;
- int clear=0;
int enc_err;
SSL_SESSION *sess;
SSL3_RECORD *rr;
- unsigned int mac_size;
+ unsigned int mac_size, orig_len;
unsigned char md[EVP_MAX_MD_SIZE];
- int decryption_failed_or_bad_record_mac = 0;
- unsigned char *mac = NULL;
-
rr= &(s->s3->rrec);
sess = s->session;
@@ -416,12 +412,16 @@ dtls1_process_record(SSL *s)
rr->data=rr->input;
enc_err = s->method->ssl3_enc->enc(s,0);
- if (enc_err <= 0)
+ /* enc_err is:
+ * 0: (in non-constant time) if the record is publically invalid.
+ * 1: if the padding is valid
+ * -1: if the padding is invalid */
+ if (enc_err == 0)
{
- /* To minimize information leaked via timing, we will always
- * perform all computations before discarding the message.
- */
- decryption_failed_or_bad_record_mac = 1;
+ /* For DTLS we simply ignore bad packets. */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto err;
}
#ifdef TLS_DEBUG
@@ -431,45 +431,62 @@ printf("\n");
#endif
/* r->length is now the compressed data plus mac */
- if ( (sess == NULL) ||
- (s->enc_read_ctx == NULL) ||
- (s->read_hash == NULL))
- clear=1;
-
- if (!clear)
+ if ((sess != NULL) &&
+ (s->enc_read_ctx != NULL) &&
+ (EVP_MD_CTX_md(s->read_hash) != NULL))
{
- /* !clear => s->read_hash != NULL => mac_size != -1 */
- int t;
- t=EVP_MD_CTX_size(s->read_hash);
- OPENSSL_assert(t >= 0);
- mac_size=t;
-
- if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
+ /* s->read_hash != NULL => mac_size != -1 */
+ unsigned char *mac = NULL;
+ unsigned char mac_tmp[EVP_MAX_MD_SIZE];
+ mac_size=EVP_MD_CTX_size(s->read_hash);
+ OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
+
+ /* kludge: *_cbc_remove_padding passes padding length in rr->type */
+ orig_len = rr->length+((unsigned int)rr->type>>8);
+
+ /* orig_len is the length of the record before any padding was
+ * removed. This is public information, as is the MAC in use,
+ * therefore we can safely process the record in a different
+ * amount of time if it's too short to possibly contain a MAC.
+ */
+ if (orig_len < mac_size ||
+ /* CBC records must have a padding length byte too. */
+ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+ orig_len < mac_size+1))
{
-#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
- al=SSL_AD_RECORD_OVERFLOW;
- SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
+ al=SSL_AD_DECODE_ERROR;
+ SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
-#else
- decryption_failed_or_bad_record_mac = 1;
-#endif
}
- /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
- if (rr->length >= mac_size)
+
+ if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
{
+ /* We update the length so that the TLS header bytes
+ * can be constructed correctly but we need to extract
+ * the MAC in constant time from within the record,
+ * without leaking the contents of the padding bytes.
+ * */
+ mac = mac_tmp;
+ ssl3_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len);
rr->length -= mac_size;
- mac = &rr->data[rr->length];
}
else
- rr->length = 0;
- i=s->method->ssl3_enc->mac(s,md,0);
- if (i < 0 || mac == NULL || memcmp(md, mac, mac_size) != 0)
{
- decryption_failed_or_bad_record_mac = 1;
+ /* In this case there's no padding, so |orig_len|
+ * equals |rec->length| and we checked that there's
+ * enough bytes for |mac_size| above. */
+ rr->length -= mac_size;
+ mac = &rr->data[rr->length];
}
+
+ i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
+ if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
+ enc_err = -1;
+ if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
+ enc_err = -1;
}
- if (decryption_failed_or_bad_record_mac)
+ if (enc_err < 0)
{
/* decryption failed, silently discard message */
rr->length = 0;